Various types of dispensers are commonly used to add seasonings and flavorings to foods and beverages. Typically, for example, seasonings such as table salt and ground pepper are dispensed from shakers comprising single-chamber containers having top walls containing a plurality of apertures to allow the contained material to be dispensed upon inverting and shaking the shakers. The number and sizes of the apertures generally vary with the type of material to be dispensed.
Many prior dispensers address the problem of over-dispensing or, more particularly, the need to dispense a controlled amount when desired. Some of the prior dispensers comprise two chambers and a delivery tube. The first chamber forms a material reservoir. The second chamber is calibrated for measuring the material. One chamber is located above the other. The delivery tube communicates with the measuring chamber at one end, extends through the reservoir chamber, and at the opposite end communicates with the exterior of the dispenser. Bettman U.S. Pat. No. 1,084,530; Buckland U.S. Pat. No. 1,270,262; Abbott U.S. Pat. No. 1,707,967; Cagliostro U.S. Pat. No. 1,877,808; Trautvetter U.S. Pat. No. 1,763,449; Gordon U.S. Pat. No. 2,644,616; and Feuerstein et al. U.S. Pat. No. 4,434,921 are exemplary of this type of construction.
Eckman U.S. Pat. No. 4,961,521 discloses an adjustable metered dispenser that is capable of dispensing seasonings such as salt and pepper. Eckman's dispenser comprises two chambers arranged in series. The first chamber is a material reservoir and the second chamber is a measuring chamber. Eckman's dispenser includes the ability to shut off the metering chamber from the reservoir chamber when the material is dispensed. Thus, in order avoid over-dispensing, the user must be sure that the passageway between the two chambers is closed.
Krupic, et al. U.S. Pat. No. 5,169,049 also discloses a shaker for dispensing seasonings such as salt and pepper. The device comprises three chambers: a material reservoir chamber, a measuring chamber and a dispensing chamber. The reservoir chamber is disposed between the measuring chamber and the dispensing chamber and a delivery tube communicates with the measuring chamber and the dispensing chamber. When the dispenser is in the non-use position, the measuring chamber is on the bottom. Upon use, the dispenser is inverted, and the dispensing chamber is filled with the material from the measuring chamber. The material must then be dispensed by shaking the dispenser in the inverted position to evacuate the material from the dispensing chamber via a plurality of apertures. In order to prevent over dispensing, one embodiment of the device includes shake-back guards within the reservoir chamber.